Electrochemical investigation of the corrosion behaviour of mild steel in 2 M HCl solution in presence of 1-dodecyl-4-methoxy pyridinium bromide

Electrochemical measurements were performed to investigate the effectiveness of the cationic surfactant; 1-dodecyl-4-methoxy pyridinium bromide as corrosion inhibitor for mild steel in 2 M HCl solution. It was found hat the percentage inhibition efficiency (η,%) increased with the increase of the surfactant concentration until critical micelle concentration (cmc) is reached. Potentiostatic polarization measurements show that this surfactant suppressed both cathodic and anodic processes of mild steel corrosion in 2 M HCl solution by adsorption on mild steel surface according to Langmuir adsorption isotherm. Thus, it can be classified as mixed-type inhibitor. Adsorption equilibrium constant (Kads) and free energy of adsorption (ΔGads) were calculated and discussed. The data obtained from electrochemical impedance spectroscopy (EIS) were analyzed to model the corrosion inhibition process through equivalent circuit.